I am somewhat skeptical of the exhibit of the so-called "Aztec calendar wheels". The calendar described is that of the Maya (though the Aztecs might have used it also). The Aztecs were the rulers of central Mexico circa 1300-1550 A.D. I'd be surprised if more about them than there general location (northern Mexico) is known prior to this. I'd be very surprised if a physical artifact could be identified as "Aztec" as early as 1000 B.C., even if the Aztecs are known to have existed that early as a self-aware entity. Finally, though modern commentators use the interlocking-gear conceit to describe the interaction of the Maya's 260-day sacred almanac with their larger time-units, I have never heard that any of the meso-Americans who used the 260-day sacred almanac ever built a physical device, prior to European contact, consisting of interlocking gears to represent their calendrical system.